We now have %FinalizeOptimization() to block until all concurrent
compile jobs are done.

Bug: v8:7790,v8:12004
Change-Id: Ibb9955be06957b3f395b680e9be570c7c3ec0dcb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3086478
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76231}